1. Field of the Invention
The present invention relates to a card edge connector and, more particularly, to a card edge connector used for inserting and fitting an electronic card, that has an electronic device packaged thereon, into a connector of an electronic equipment. The present invention also relates to a method of manufacturing the, card edge connector, and to an electronic card and an electronic equipment using the card edge connector.
2. Description of Related Art
As is well known in the art, when a card-shaped printed circuit board is to be implemented in an electronic equipment, a generally adopted method is to provide a card edge connector at an end portion of the printed circuit board, and to insert and fit the card edge connector into a connector of the electronic equipment.
FIG. 1 is a sectional view showing an example of a prior art card edge connector and illustrating the use thereof. In the illustrated example, a construction is adopted such that an electronic equipment is provided with a connector 51 having a socket structure, and a card edge connector 53 as a plug is directly inserted and fitted into the connector 51. The connector 51 has a plurality of wire-type connector contacts 54 in the socket portion into which the card edge connector is to be inserted. On the other hand, the card edge connector 53 is formed integrally with a printed circuit board (not shown) at an end thereof, and has electrode contacts 55 corresponding to the connector contacts 54 disposed with wirings on both sides of its body 56. When the card edge connector 53 is inserted into the connector 51 and fitted into it, the electrode contacts 55 are pressed onto the connector contacts 54, so as to achieve electrical connection between them. In the case of the card edge connector 53 as shown in FIG. 1, however, a large force is required for insertion into and extraction from the connector, and this may sometime cause damage to the connector portion due to excessive force exerted in the operation. This is caused by the shape of the connector body 56 which is prismatic at the end corner as shown by the arrow A. There is also a problem with the electrode contacts 55 that metal debris may fall off at the segment 55a. 
In order to overcome problems associated with the excessive force exerted during insertion and extraction of the card edge connector, it has been known to chamfer the end of the connector body 56 to remove the prismatic corner edge thereof as shown in FIG. 2. However, in the card edge connector 53 as shown in FIG. 2, the terminating portions of the electrode contacts 55 are of a prismatic shape as shown by an arrow B so that difficulties may arise in the insertion of the connector, and problems may often arise in the insertion and extraction of the connector such as separation of the contacts, breaking of the prismatic edge and the falling-off of fine metal debris. When the fine metal debris of the electrode contacts enters into inside of the electronic equipment, serious problems, for example, an electrical short circuit or the like, may arise. Although it has been proposed to form the electrode contacts 55 as a thin film deposited on the card edge connector 53 in order to avoid the falling-off of metal debris, this method is not a feasible solution because, with increase of the amount of information processed, current electronic equipment is generally required to be able to pass a correspondingly large current. Countermeasures such as a shift in terminating position of the electrode contacts 55, a change of the angle of chamfering at the end of the connector body 56, or the like, do not lead to an essential solution of the problem.
FIG. 3 shows a card edge connector that has been developed in order to solve the above described problems. In this card edge connector 53, the end of the connector body 56 is cut in the shape of wedge to form an inclined surface 56a so as to make it easy to insert the electrode contacts 55 between the connector contacts 54. In this cutting operation, the electrode contacts 55 are also cut to obtain the effect of removing the prismatic edge of the contacts. However, in cutting of the electrode contacts 55, burrs may arise in the corner portion shown by an arrow C, giving rise to another problem that a finishing operation to remove the burrs is necessary. Also, in the case of a card edge connector of such a construction, the inclined surface 56a formed by the cutting is a rough surface so that repeated insertion and extraction of the connector tends to damage the connector contacts 55.
FIG. 4 is a view showing a card edge connector that has been developed to resolve the problems as described above. In this card edge connector 53, after the end of the connector body 56 is cut in a shape of wedge to form a rounded inclined surface, electrode contacts 55 are formed so as to cover almost whole of the inclined surface. Thus, the electrode contacts 55 are formed continuously from the wired surface of the printed circuit board to the end surface at the tip of the connector body 56. However, in the case of this card edge connector, multiple steps are required in the manufacturing process, and the manufacturing operation becomes very complicated leading, inevitably, to an increase in cost.